In a highly integrated semiconductor component (such as a radio frequency (RF) circuit), different circuit blocks such as a power amplifier, a mixer, a voltage controlled oscillator (VCO), and so forth may benefit from bipolar transistors having different characteristics. These different characteristics include, for example, current gain (Beta), unity current gain frequency (fT), maximum oscillation frequency (fMAx), bipolar transistor base resistance (RB), bipolar transistor collector-base junction capacitance (CJC), bipolar transistor emitter-base junction capacitance (CJE), breakdown voltages (BVCBO), and so forth.
A number of silicon-based products operating in the high frequency bands use silicon germanium bipolar complementary metal oxide semiconductor (SiGe BiCMOS) technologies. An approach in a SiGe BiCMOS process to provide multiple bipolar transistor characteristics can be through the modulation of the collector doping using a specific mask in order to tailor the collector doping profile to achieve transistors with different breakdown voltages (BVCBO). However, the main characteristics of a SiGe heterojunction bipolar transistor (HBT) are determined by the base doping profile, which is a function of the dopants introduced during the epitaxial base growth.